/*******************************************************************************
 *   The MIT License (MIT)
 *
 *   Copyright (c) 2014-2017 Marc de Verdelhan, 2017-2018 Ta4j Organization 
 *   & respective authors (see AUTHORS)
 *
 *   Permission is hereby granted, free of charge, to any person obtaining a copy of
 *   this software and associated documentation files (the "Software"), to deal in
 *   the Software without restriction, including without limitation the rights to
 *   use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 *   the Software, and to permit persons to whom the Software is furnished to do so,
 *   subject to the following conditions:
 *
 *   The above copyright notice and this permission notice shall be included in all
 *   copies or substantial portions of the Software.
 *
 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 *   FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 *   COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 *   IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 *   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *******************************************************************************/
package org.ta4j.core.indicators.pivotpoints;

import org.ta4j.core.Bar;
import org.ta4j.core.indicators.RecursiveCachedIndicator;
import org.ta4j.core.num.Num;

import java.util.List;

import static org.ta4j.core.num.NaN.NaN;

/**
 * DeMark Reversal Indicator.
 * </p>
 * @see <a href="http://stockcharts.com/school/doku.php?id=chart_school:technical_indicators:pivot_points">
 *     http://stockcharts.com/school/doku.php?id=chart_school:technical_indicators:pivot_points</a>
 */
public class DeMarkReversalIndicator extends RecursiveCachedIndicator<Num> {

    private final DeMarkPivotPointIndicator pivotPointIndicator;
    private final DeMarkPivotLevel level;
    private final Num TWO;

    public enum DeMarkPivotLevel{
        RESISTANCE,
        SUPPORT,
    }

    /**
     * Constructor.
     * <p>
     * Calculates the DeMark reversal for the corresponding pivot level
     * @param pivotPointIndicator the {@link DeMarkPivotPointIndicator} for this reversal
     * @param level the {@link DeMarkPivotLevel} for this reversal (RESISTANT, SUPPORT)
     */
    public DeMarkReversalIndicator(DeMarkPivotPointIndicator pivotPointIndicator, DeMarkPivotLevel level) {
        super(pivotPointIndicator);
        this.pivotPointIndicator = pivotPointIndicator;
        this.level =level;
        TWO = numOf(2);
    }

    @Override
    protected Num calculate(int index) {
        Num x = pivotPointIndicator.getValue(index).multipliedBy(numOf(4));
        Num result;

        if(level == DeMarkPivotLevel.SUPPORT){
            result = calculateSupport(x, index);
        }
        else{
            result = calculateResistance(x, index);
        }

        return result;

    }

    private Num calculateResistance(Num x, int index) {
        List<Integer> barsOfPreviousPeriod = pivotPointIndicator.getBarsOfPreviousPeriod(index);
        if (barsOfPreviousPeriod.isEmpty()){
            return NaN;
        }
        Bar bar = getTimeSeries().getBar(barsOfPreviousPeriod.get(0));
        Num low = bar.getMinPrice();
        for(int i: barsOfPreviousPeriod){
            low = getTimeSeries().getBar(i).getMinPrice().min(low);
        }

        return x.dividedBy(TWO).minus(low);
    }

    private Num calculateSupport(Num x, int index){
       List<Integer> barsOfPreviousPeriod = pivotPointIndicator.getBarsOfPreviousPeriod(index);
       if (barsOfPreviousPeriod.isEmpty()) {
           return NaN;
       }
       Bar bar = getTimeSeries().getBar(barsOfPreviousPeriod.get(0));
       Num high = bar.getMaxPrice();
       for(int i: barsOfPreviousPeriod){
           high = getTimeSeries().getBar(i).getMaxPrice().max(high);
       }

       return x.dividedBy(TWO).minus(high);
   }
}
